Integration of feature extraction, attribute combination and image segmentation for object delineation on seismic images

Automatic geological interpretation, specifically modeling salt dome and fault detection, is controversial task on seismic images from complex geological media. In advanced techniques of seismic interpretation and modeling, various strategies are utilized for combination and integration different information layers to obtain an image adequate for automatic extraction of the object from seismic data. Efficiency of the selected feature extraction, data integration and image segmentation methods are the most important parameters that affect accuracy of the final model. Moreover, quality of the seismic data also affects confidence of the selected seismic attributes for integration. The present study proposed a new strategy for efficient delineation and modeling of geological objects on the seismic image. The proposed method consists of extraction specific features by the histogram of oriented gradients (HOG) method, statistical analysis of the HOG features, integration of features through hybrid attribute analysis and image classification or segmentation. The final result is a binary model of the target under investigation. The HOG method here modified accordingly for extraction of the related features for delineation of salt dome and fault zones from seismic data. The extracted HOG parameter then is statically analyzed to define the best state of information integration. The integrated image, which is the hybrid attribute, then is used for image classification, or image segmentation by the image segmentation method. The seismic image labeling procedure performs on the related seismic attributes, evaluated by the extracted HOG feature. Number of HOG feature and the analyzing parameters are also accordingly optimized. The final image classification then is performed on an image which contains all the embedded information on all the related textural conventional and statistical attributes and features. The proposed methods here apply on four seismic data examples, synthetic model of salt dome and faults and two real data that contain salt dome and fault. Results have shown that the proposed method can more accurately model the targets under investigation, compared to advanced extracted attributes and manual interpretations

Cementation exponent estimate in carbonate reservoirs: A new method

There are two approaches for measuring hydrocarbon saturation: well log interpretation and usually developed formulas. Archie’s equation is one of the most fundamental equations used for water saturation calculation. Archie’s equation includes three factors: cementation factor, tortuosity and saturation exponent. Archie determines these factors based on lab results in sandstone and provides fixed value for them. Carbonate reservoirs have a variety of textures, shapes and distribution of pores; therefore, the mentioned factors, especially cementation are not considered constant. In this study, the relationship between cementation factor and density log was examined because cementation factor is defined as a parameter that has a close relationship with density. By calculating the matrix density and accordance factor between the matrix density and cementation factor from core’s analysis, a log will be generated that can estimate the variation of cementation factor around the borehole. This method is useable for calculating the cementation factor in carbonate rocks.   Keywords: Cementation factor, carbonate reservoir, density, new method, exponents.</jats:p

Determination of Archie’s Tortuosity Factor from Stoneley Waves in Carbonate Reservoirs

One of the fundamental equations in calculate the saturation of fluid in hydrocarbon reservoirs is the Archie’s equation. In addition to the parameters measured by well logging such as porosity and resistivity, there are others parameters that called Archie’s coefficients. Archie provides constant values for this coefficient base on experimental core’s data, accordance with saturation formula in sandstone. In carbonate reservoirs nevertheless the sandstone reservoirs, high heterogeneity, variety in lithology and texture, shape and distribution of pores, due to this coefficient is not constant. So, variation of tortuosity as a coefficient that depends on the way correlation between pores, is high and considering a constant value due to error in calculation of fluid saturation. In this study, with the stoneley waves measured from DSI tools and required calculation, the value of tortuosity coefficient calculated continuously in well no.10 Darkhovin field. The regression of calculated values with the core data is 83.16 percent, that showed this method is useable for calculation the tortuosity.</jats:p